The US Navy recently declared that it has no intention of listening to the California Coastal Commission’s recommendations on mitigating the impact of its sonar and offshore training drills on marine mammals.

The commission had asked the Navy to declare some Southern California coastal areas off-limits for training. Back in March, the commission had objected to the Navy's assertion that the drills did not harm marine mammals, declaring by unanimous vote that the claim was not supported by scientific evidence. The commission had said that the Navy’s testing activities were not consistent with California coastal law.

However, in a letter to the commission dated July 31, the Navy insisted, yet again, that its “mitigation measures are effective and appropriate for avoiding and minimizing impacts for all areas.” The Navy says that it doesn’t need to comply with California law, it only needs to consult with the coastal commission.

The Navy plans to step up its training drills, which would involve using sonar waves and underwater detonations, off the California and Hawaiian coasts over the next five years starting January 2014. It says it needs to conduct these training exercises because nations hostile to the US, such as North Korea, are building submarines that are quieter that before, making them harder to detect.

As part of the practice, the Navy would run more than 10,000 hours of the same high-intensity military sonar each year that has killed and injured whales around the globe. It will also detonate more than 50,000 underwater explosives off the Southern California coast.

Scientists have repeatedly linked Navy sonar to several mass dolphin and whale strandings around the world. Marine mammals, especially whales and dolphins, rely on their acute and highly specialized hearing for communication, navigation, and detecting predators. Here's how Mark Palmer, associate director of Earth Island Institute's International Marine Mammal Project described the impact of sonar on whales and dolphins today: "Imagine someone shining a bright light in your eyes while you are trying to go about your daily business. Then imagine a very loud noise that can wreak havoc on your ears. The noise of some military sonars are the equivalent of standing next to the space shuttle on take-off. Such loud sounds can actually kill dolphins and whales."

“The Coastal Commission has offered reasonable measures that take into account the Navy’s need for flexibility while affording greater protection to vulnerable species,” Michael Jasny, marine mammal project director at the Natural Resources Defense Council said in a statement. “The Navy’s refusal to adopt any of these measures puts California’s marine life in jeopardy.”

By the Navy’s own estimates, its upcoming exercises could kill 130 marine mammals in five years and cause hearing loss in 1,600 and disrupt foraging and mating activities of these ocean inhabitants. It estimates that increased sonar training will significantly harm marine mammals off US coasts more than 10 million times over the next five years.

The Navy’s decision comes at a time when several new studies show that its activities off the California coast are harming marine mammals like the blue whales and beaked whales, far more than was previously estimaed. For beaked whales, a species that’s acutely sensitive to sonar waves, the impact of the naval exercises would be especially devastating. A study published earlier this year found that beaked whale populations have indeed declined substantially in the California Current over the past 20 years, and suggests that the Navy’s range may have become a population sink, making it difficult for them to breed or bring their calves to maturity. Yet another recent report by the Southern California Behavioral Response Study found that the Navy’s frequent sonar training poses significant risks to the recovery of endangered blue whales, whose numbers down to only about 10,000.

The Navy says it is open to negotiation but it has so far refused to follow any of the commission’s recommended mitigation measures, such as avoiding exercises in the key foraging habitat for the endangered blue whale. "We are still in talks with the Navy though it doesn't appear that they are willing to make any major concessions at the moment," Mark Delaplaine, manager of California Coastal Commission's federal consistency division, told me over the phone this afternoon. The commission is waiting for the federal National Marine Fisheries Service, that has jurisdiction over Naval operations in US waters, to weigh in on the issue, he said.

“It is past time the US Navy recognized its responsibility to act in concert with other governmental agencies and programs,” Gershon Cohen, co-director Earth Island Institute’s Great Whale Conservancy project, said today. “The US Government, acting through the Marine Mammal Protection Act, has a responsibility to protect marine mammals. Last year the Coast Guard for the first time acknowledged it had a role to play in marine mammal protection when it forwarded recommendations related to shipping lane locations along the coast of California. Although their recommendations were not sufficient to truly address the issue of ship strikes, they at least demonstrated a willingness to engage on the issue. The Navy should take a similar tack. Their sonar exercises have been clearly shown to be extremely harmful to marine mammals and should be aborted, just as they need to stand down from their opposition to the use of near-shore international waters for ship transits between LA and SF though critical blue whale feeding habitat.”